The present invention relates generally to diagnostic and therapeutic dermatological devices and methods that measure physical characteristics of tissue, such as, the skin.
Dermatological devices are used to improve a variety of skin conditions, such as removal of unwanted hair, skin rejuvenation, removal of vascular lesions, acne treatment, treatment of cellulite, pigmented lesions and psoriasis, tattoo removal, treatment of skin and other cancers, etc. Many of these devices typically target a chromophore in the tissue of the subject under treatment. Depending on the procedure, such a chromophore may be, for example, melanin, hemoglobin, lipid, water, or pigment of a tattoo.
Optimal use of these devices depends, at least in part, on accurate identification of the subject's skin pigmentation so that proper treatment parameters can be used. However, commonly used methods of skin typing are not generally based on actual measurements of the chromophores of interest, such as the amount of melanin in the skin. For example, the commonly used Fitzpatrick skin type scale, which ranges from very fair (skin type I) to very dark (skin type VI), is based solely on a person's complexion and response to sun exposure. In addition, such conventional skin typing methods do not take into account variations in the concentration of a chromophore in different parts of an individual's skin. For example, although different parts of an individual's skin can exhibit different melanin concentrations, the Fitzpatrick scale provides only a single skin type for that individual. As such, the use of such conventional skin typing methods may result in complications during treatment, such as burns, scars, or ineffective treatment.
Therefore, a need exists for dermatological and other devices and methods that can accurately and efficiently determine physical characteristics of a person's skin, such as, for example, skin melanin optical density (MOD), blood content, collagen content, and/or hydration. In addition, improved safety mechanisms are needed for dermatological devices so that they can be used for non-professional uses, such as home use.